sqlkev said:
I think you are placing line arrays in some weird conditional
rule category.
A line array is just a speaker with more drivers. It will work
in a small room or a large room. Properly designed, it will play
any music and even play test tones. It doesn't care.
Just because the line array has more SPL potential and can
offer very low distortion, why alienate the array for only
certain applications ?
Here's a little secret, I don't like to give them out in public.
My future line array will have a toggle switch for each driver.
Care to guess why? :hehehe:
thylantyr said:
You just want to do away with the volume control. Switch on the speakers to determine how loud you want the music.
Wow interesting read, if you're looking for a nice midwoofer for the array. What about Audiotechnology 15H??
One question for Tyr, a lot of drivers together have very low distortion. But I cannot believe that the resolution will be better than one single drive unit. Because the distorion signature will be the same.
One question for Tyr, a lot of drivers together have very low distortion. But I cannot believe that the resolution will be better than one single drive unit. Because the distorion signature will be the same.
I found a relativly low mass Hi Eff. driver (low fs):
http://www.madisound.com/cgi-bin/index.cgi?cart_id=5885167.18483&pid=362
(..don't know what force factor is though.)
For the price it seems to be a pretty good deal (..haven't done any modeling with it though).
http://www.madisound.com/cgi-bin/index.cgi?cart_id=5885167.18483&pid=362
(..don't know what force factor is though.)
For the price it seems to be a pretty good deal (..haven't done any modeling with it though).
Taco said:
Audible distortion is linked to driver SPL. Keep single driver
SPL low and let the array gain raise the overal SPL level.
Result, low array distortion at higher SPL than the single driver.
The driver distortion signature is moot if you can't hear it.
Only until you raise line array SPL to extreme levels will driver
distortion be audible. To raise SPL with the same watt,
quantity of drivers and how you wired them are the two
variables to boost array performance {not counting the other
obvious design issues}. If you make sacrifies to both those
variables, then your array is compromised, ie an array of
2 drivers ins't much of a line array is it? An array wired for
higher impedance isn't going to offer as much as it could.
Maybe I am a little thick, but I don't see how wiring for low impedance (increased voltage sensitivity as a result) is going to improve the line array drivers' inherent distortion characteristics.
Each driver sees a voltage across its terminals, a current flows and the cone moves. This movement is less if there are multiple drivers to make a given SPL. This results in less distortion than if a lower number of the same drivers were asked to make the same SPL.
As far as distortion goes however, to the individual driver it doesn't matter whether that voltage comes directly from an amplifier, through a couple other drivers or through a 100K ohm resistor. As long as there is enough voltage and current available to allow the driver to make its share of the total SPL, the distortion products are unchanged. The total array distortion is still reduced compared to a single driver at the same SPL.
On the other hand, if the impedance goes too low, the amplifier will have a more difficult time driving the load. Even if the protection circuits don't kick in, distortion increases with lower load impedance.
Of course, if wired for higher impedance, the array must be driven by an amplifier with enough voltage swing capability to drive it properly. This is an easier design point than designing for a low impedance load. I'd bet it's easier reach a given distortion target into 16 ohms than into 1 ohm at 100W into either load.
Besides requiring less excursion per driver than a single driver speaker, arrays have the benefit of absorbing less power per driver for a given SPL. This means there is less power compression. Low power compression is probably what gives high efficiency speakers their "liveliness" that so many love. The voice coils don't heat up as much and the parameters don't change with normal listening power levels.
Does this make sense or am I out to lunch?
Each driver sees a voltage across its terminals, a current flows and the cone moves. This movement is less if there are multiple drivers to make a given SPL. This results in less distortion than if a lower number of the same drivers were asked to make the same SPL.
As far as distortion goes however, to the individual driver it doesn't matter whether that voltage comes directly from an amplifier, through a couple other drivers or through a 100K ohm resistor. As long as there is enough voltage and current available to allow the driver to make its share of the total SPL, the distortion products are unchanged. The total array distortion is still reduced compared to a single driver at the same SPL.
On the other hand, if the impedance goes too low, the amplifier will have a more difficult time driving the load. Even if the protection circuits don't kick in, distortion increases with lower load impedance.
Of course, if wired for higher impedance, the array must be driven by an amplifier with enough voltage swing capability to drive it properly. This is an easier design point than designing for a low impedance load. I'd bet it's easier reach a given distortion target into 16 ohms than into 1 ohm at 100W into either load.
Besides requiring less excursion per driver than a single driver speaker, arrays have the benefit of absorbing less power per driver for a given SPL. This means there is less power compression. Low power compression is probably what gives high efficiency speakers their "liveliness" that so many love. The voice coils don't heat up as much and the parameters don't change with normal listening power levels.
Does this make sense or am I out to lunch?
Here are the speakers I heard as a teenager at my uncles house. The link is to a pair for sale on Audiogon.
http://cls.audiogon.com/cgi-bin/cls.pl?spkrfull&1163184749
There is nothing I have ever heard that comes close. 12 planar midranges, 24 planar tweeters front firing 4 rear firing, 6 bass drivers (10" I believe).... per side.
I have been hooked ever since. My first serious DIY effort was the Zalytron array with 12 Axon 6S1 drivers and a Raven 2 per side. I know they are not a true array, but I could care less. They do everything arrays are known for and the only drawback is vertical dispersion on the tweeter. When these drivers first came out Zalytron bought a bulk of them and then got Joe D'Appolito to work up the array designs. I waited patiently as he worked out the design over several months. The initial design used 4 Axon tweeters in a center cluster. I decided that the Raven was the better choice ( I thought that would be the last pair I would build Ha!!). So Joe worked up a crossover for the Raven as well. No regrets on my decisions. The square boxes are not the prettiest thing, but close your eyes and they do things that conventional designs simply cannot do.
I have now had to move the damn things 4 times. At 7 foot 6 inches tall and something like 13X21" footprint using 1.5" MDF all around. They are monseters to move. They are now in my basement roon and I don't plan on removing them in one piece.
DaveM
http://cls.audiogon.com/cgi-bin/cls.pl?spkrfull&1163184749
There is nothing I have ever heard that comes close. 12 planar midranges, 24 planar tweeters front firing 4 rear firing, 6 bass drivers (10" I believe).... per side.
I have been hooked ever since. My first serious DIY effort was the Zalytron array with 12 Axon 6S1 drivers and a Raven 2 per side. I know they are not a true array, but I could care less. They do everything arrays are known for and the only drawback is vertical dispersion on the tweeter. When these drivers first came out Zalytron bought a bulk of them and then got Joe D'Appolito to work up the array designs. I waited patiently as he worked out the design over several months. The initial design used 4 Axon tweeters in a center cluster. I decided that the Raven was the better choice ( I thought that would be the last pair I would build Ha!!). So Joe worked up a crossover for the Raven as well. No regrets on my decisions. The square boxes are not the prettiest thing, but close your eyes and they do things that conventional designs simply cannot do.
I have now had to move the damn things 4 times. At 7 foot 6 inches tall and something like 13X21" footprint using 1.5" MDF all around. They are monseters to move. They are now in my basement roon and I don't plan on removing them in one piece.
DaveM
No your right Bob.
The drivers still have the same power handling, thermal and excursion limits and therefor distortion and max SPL limits too.
All the lower impedance wiring does is make the seemingly more efficient through current and loading on the amp(s).
When all is said and done, given enough power the drivers will perform identically whether wired for higher or lower impedance ie. max SPL, excursion and distortion at a given SPL figure will be identical across the board.
The real question is do my amps drive a 0.5ohm load and drive a low impedance array or do I have a bunch of amplifiers that will drive an 8ohm load that will fully exploit all the drivers power handling limits. Eitherway you get the same results although providing you have a suitable amplifier, the low impedance wiring may better use that and I think that's what Thy was getting at.
The drivers still have the same power handling, thermal and excursion limits and therefor distortion and max SPL limits too.
All the lower impedance wiring does is make the seemingly more efficient through current and loading on the amp(s).
When all is said and done, given enough power the drivers will perform identically whether wired for higher or lower impedance ie. max SPL, excursion and distortion at a given SPL figure will be identical across the board.
The real question is do my amps drive a 0.5ohm load and drive a low impedance array or do I have a bunch of amplifiers that will drive an 8ohm load that will fully exploit all the drivers power handling limits. Eitherway you get the same results although providing you have a suitable amplifier, the low impedance wiring may better use that and I think that's what Thy was getting at.
Parallel or series only matters for the *voltage* sensitivity. The overall sensitivity (power per watt input) increases by 3 dB each time you double the number of drivers.
As for distortion, Linkwitz had intersting results showing that contrary to expectations, nonlinear distorion does *not* just depend on SPL, or in other words - the lesser drivers *will* have what he calls "unreasonably high distortion" even at fairly low SPL. Link:
unreasonably high distorion in midrange drivers
As for energy storage (linear distorion, AKA resonances), these will not decrease when using multiple drivers, and therefore resolution really is not to be expected to increase when using more drivers. I see line arrays mostly as a different way of illuminating the room, and to some extent about ease of high SPL, not so much as a way of gaining resolution.
Conclusion: It's worth using good drivers even in a line array.
BTW glad Shin you liked my modular suggestion (though you have since veered off into the lure of designing the speaker the way of "looks first, sound later" ). I actually put quite some thought into this, because I wanted to try it for myself one far away day in the future... so my ideas of driver choice and dimensions, modularity and ease of build, all there for a reason, although it looks so boringly simple. The SS8531 are said to be very natural and detailed, yet measure great as well, as per Zaph's. They have high excursion, very high Sd for a supposed 6.5", and therefore high volume displacement. The BG Neos in Zaph's test beat the other ribbon competion by a wide margin in Zaph's tests, and can be crossed much, much lower than all the other ribbons and planars (he only tested the 3" model but the 8" is the same technology, and both are of a newer generation than their already well respected longer RD series) . They have a resonance at 12.5k, I suppose that's what Thy was referring to, which is extremely clean in shape and therefore easy to notch out. And the capability of the BG Neo8 to cross as low as 500 Hz if you insist, would help a lot with depth and side offset problems which come about through the necessary side-by-side mounting of tweeter vs woofer, because at say 900 Hz your wavelength is half a meter, vs 21 cm at 1600 Hz. All that's left is to give the thing good looks, and maybe to play with baffle shape to smoothen response.
As for distortion, Linkwitz had intersting results showing that contrary to expectations, nonlinear distorion does *not* just depend on SPL, or in other words - the lesser drivers *will* have what he calls "unreasonably high distortion" even at fairly low SPL. Link:
unreasonably high distorion in midrange drivers
As for energy storage (linear distorion, AKA resonances), these will not decrease when using multiple drivers, and therefore resolution really is not to be expected to increase when using more drivers. I see line arrays mostly as a different way of illuminating the room, and to some extent about ease of high SPL, not so much as a way of gaining resolution.
Conclusion: It's worth using good drivers even in a line array.
BTW glad Shin you liked my modular suggestion (though you have since veered off into the lure of designing the speaker the way of "looks first, sound later"
). I actually put quite some thought into this, because I wanted to try it for myself one far away day in the future... so my ideas of driver choice and dimensions, modularity and ease of build, all there for a reason, although it looks so boringly simple. The SS8531 are said to be very natural and detailed, yet measure great as well, as per Zaph's. They have high excursion, very high Sd for a supposed 6.5", and therefore high volume displacement. The BG Neos in Zaph's test beat the other ribbon competion by a wide margin in Zaph's tests, and can be crossed much, much lower than all the other ribbons and planars (he only tested the 3" model but the 8" is the same technology, and both are of a newer generation than their already well respected longer RD series) . They have a resonance at 12.5k, I suppose that's what Thy was referring to, which is extremely clean in shape and therefore easy to notch out. And the capability of the BG Neo8 to cross as low as 500 Hz if you insist, would help a lot with depth and side offset problems which come about through the necessary side-by-side mounting of tweeter vs woofer, because at say 900 Hz your wavelength is half a meter, vs 21 cm at 1600 Hz. All that's left is to give the thing good looks, and maybe to play with baffle shape to smoothen response.
If you're heading for .5 ohms, you're pretty much DIY amps anyway. A nominal load of 4 ohms is OK, but when you say .5 nominal you may end up with dips to .3 or less. Cable and connection losses will eat a significant part of the power developed.
I think I'd prefer to go with each driver or two driven by a Symasym or GB150 - good quality amps on small boards. You could stack a bunch of either on some decent size heat sinks. The amps could share a common transformer and main bank of caps as long as they have some local decoupling.
That should be much easier and more efficient use of power than trying to make an amp (and speaker cables) that will deliver 20 amps to get a mere 100 watts RMS into the speaker.
I think I'd prefer to go with each driver or two driven by a Symasym or GB150 - good quality amps on small boards. You could stack a bunch of either on some decent size heat sinks. The amps could share a common transformer and main bank of caps as long as they have some local decoupling.
That should be much easier and more efficient use of power than trying to make an amp (and speaker cables) that will deliver 20 amps to get a mere 100 watts RMS into the speaker.
Thx Bob/ MBK for elaborating on my questions.
The Scanspeak 18W8531 has not that much resolution, I used this woofer and those sliced cones have a engineered sound to it. The sound is impressive, but I think you can do better with Seas Excel (also used these woofers, they sound more neutral with lots of detail).
The Scanspeak 18W8531 has not that much resolution, I used this woofer and those sliced cones have a engineered sound to it. The sound is impressive, but I think you can do better with Seas Excel (also used these woofers, they sound more neutral with lots of detail).
I think I'm going to go with my gut feeling on this one.
Raven R3.2MMX flanked by a pair of Supravox 215GMF in aperiodic cabinets. Crossover are up for debate but I'd likely look into 600-800hz with steep filters. There's also the possibility of using 1st order around 2000hz with these very wideband drivers but with caveats regarding dispertion matching. Basically with the PCXO I can try lots and see what works and what doesn't, I can even go 2.5way should I go with a higher XO point and wish to limit lobing, all sorts of thing to look at there.
Overall sensitivity would be a very good 97-98dB from 100hz-30Khz. Certainly wouldn't need huge amps to get a huge sound from that.
I've also taken an interest in wave guides recently so would like to remove the face plate on the Raven and try out different designs.
I really like the Anime look so will likely go with something along the lines of these two:
Raven R3.2MMX flanked by a pair of Supravox 215GMF in aperiodic cabinets. Crossover are up for debate but I'd likely look into 600-800hz with steep filters. There's also the possibility of using 1st order around 2000hz with these very wideband drivers but with caveats regarding dispertion matching. Basically with the PCXO I can try lots and see what works and what doesn't, I can even go 2.5way should I go with a higher XO point and wish to limit lobing, all sorts of thing to look at there.
Overall sensitivity would be a very good 97-98dB from 100hz-30Khz. Certainly wouldn't need huge amps to get a huge sound from that.
I've also taken an interest in wave guides recently so would like to remove the face plate on the Raven and try out different designs.
I really like the Anime look so will likely go with something along the lines of these two:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
And looking much nicer
Just an idea....have you tried "turning" your design 180 degrees....so that you get the "leg" in front.... would give a smaller front
About colors, I cant help thinking it would look better if you only had different colors on seperate front baffles and box....I think there should be a change in "structure" when ever you change the finish
Just an idea....have you tried "turning" your design 180 degrees....so that you get the "leg" in front.... would give a smaller front
About colors, I cant help thinking it would look better if you only had different colors on seperate front baffles and box....I think there should be a change in "structure" when ever you change the finish
Your absolutely right ... actually I think I wouldnt use black at all ... would let the design more pure and "speak" on its own
Are you sure your design is stable enough, with the added height and weight ...maybe it would benefit from two thinner "legs" .... or maybe the single "leg" could be larger in diameter, giving a beefier look ....and placed just a little bit higher on box ?
Are you sure your design is stable enough, with the added height and weight ...maybe it would benefit from two thinner "legs" .... or maybe the single "leg" could be larger in diameter, giving a beefier look ....and placed just a little bit higher on box ?
tinitus said:
More than strong enough. To highly that:
An externally hosted image should be here but it was not working when we last tested it.
Even without the rear foot the cabinets could stand stable on the plinth - in fact they did for over a week whilst I finished the foot 🙂
The bottom of the enclosure that attaches onto the 3" thick MDF plinth was heavily reinforced and I use 6x 5" large diameter screws to fasten each to the plinth. Then add the foot and its not going anywhere. For the next I could use two feet at the rear for added peace of mind but I know its not essential.
I would like a beefier "leg" though .... just for the look
Anyway I think your new dappolito design looks much much better than any of the others ... the symmetry does look something special ... and lighter still
Anyway I think your new dappolito design looks much much better than any of the others ... the symmetry does look something special ... and lighter still
Member
Joined 2003
AH!
Me LIKE!
Definitly Ultra-Fi! (..and a loudspeaker I would be envious of..)
Shin'. While you are still in the UK (perhaps around the London area?), you might ask Susan Parker to see if you can stop by and listen to her amplifier and pre amplifier.
While the transfomer cores are less than excellent (..only an M6 as opposed to one with amounts of nickle, or better yet all amorphous) - her design is very much an Ultra-Fi based amplifer (and is quite good with respect to non-linear distortion), and in particular would allow a low mass loudspeaker design to be that much better (..and 3D).
http://www.susan-parker.co.uk/zeus-about.htm
(She also has a long thread here on the Solid State forum I believe.)
Me LIKE!
Definitly Ultra-Fi! (..and a loudspeaker I would be envious of..)
Shin'. While you are still in the UK (perhaps around the London area?), you might ask Susan Parker to see if you can stop by and listen to her amplifier and pre amplifier.
While the transfomer cores are less than excellent (..only an M6 as opposed to one with amounts of nickle, or better yet all amorphous) - her design is very much an Ultra-Fi based amplifer (and is quite good with respect to non-linear distortion), and in particular would allow a low mass loudspeaker design to be that much better (..and 3D).
http://www.susan-parker.co.uk/zeus-about.htm
(She also has a long thread here on the Solid State forum I believe.)
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